From: glhurst@onr.com (Gerald L. Hurst)
Newsgroups: sci.physics
Subject: Re: Waterfall problem
Date: 11 Mar 1996 00:07:32 GMT

In article <31435B7F.1268@sover.net>, Matt Berube <mberube@sover.net> says:

>Could someone please post the answer to this problem, and how you solve 
>it. It's been bugging me for weeks.
>
>Water going over a waterfall drops 50.6 meters. How much warmer is the 
>water at the bottom than at the top?

If this is merely a high school physics problem not requiring
a correct real-life answer, simply convert the potential
energy into its heat equivalent and use the specific heat of 
water to calculate the temperature rise.

In real life, your calculation will only work if the waterfall
is sufficiently compact and voluminous enough for the magnitude
of the potential energy to grossly outweigh the potential
heating/cooling effects from simple heat exchange with the 
atmosphere and the cooling effect of evaporation.

When you repeatedly dip and pour your soup from a spoon back into
the bowl, your object in creating that little "water fall" is to
cool the liquid, not to heat it through energy conversion :)

Jerry (Ico)